On board...she was traveling even before the Voidtrecker Express? Or, with some of the things Hera's said, it's likely she's a spacefarer, isn't it.

Wormmon knows a version of this feeling. "Ken-chan's shown me many things too. I'm so happy I'm his partner Digimon!"

"....If you'd like, we can tell you more while we work," Ken offers. He doesn't want to be That Person who ruins everyone else's fun, but he also would like to contribute as much as he can, to make up for not yet being able to fight.